Precast panel building structure and method of erecting the same

ABSTRACT

Disclosed are panel twins having a pair of stressed steel bars of tendons extending over the entire span of the twins and being transversely deflected to increase tension forces therein and thereby prestress the twins and a method of posttensioning panel twins by means of adjustable couplers and turn buckles.

United States Patent Liska Feb. 1, 1972 [54] PRECAST PANEL BUILDING STRUCTURE AND METHOD OF ERECTING THE SAME [72] Inventor: Vladimir D. Liska, 2335 Broadway, Long lsland City, N.Y. 11116 [22] Filed: Nov. 6, 1968 21 Appl. No.3 773,752

[52] US. Cl ..52/91, 52/225, 52/584, 52/747 [51] Int. Cl. ..EMc 3/22, E04g 21/12 [58] Field of Search ..52/91, 94, 225, 226, 583,602, 52/125, 747, 584, 303

[56] References Cited UNITED STATES PATENTS 661,084 11/1900 Smith et a1 ..52/226 1,111,131 9/1914 Broughton ....52/91 X 2,155,121 4/1939 Finsterwalder ..52/225 X Minck ..52/602 X 2,351,856 6/1944 l-lenderson..

2,690,667 10/1954 Mauguoy ..52/225 2,180,317 11/1939 Davis 52/226 X 2,616,284 11/1952 Leontovich. ..52/303 3,300,916 1/1967 Pritzker ..52/584 X FOREIGN PATENTS OR APPLICATIONS 166,655 1/ 1956 Australia ..52/90 1,045,630 12/1958 Germany ....52/226 35,481 4/1953 Poland ..52/90 Primary ExaminerAlfred C. Perham Attorney-Lackenbach 8L Lackenbach [5 7] ABSTRACT Disclosed are panel twins having a pair of stressed steel bars of tendons extending over the entire span of the twins and being transversely deflected to increase tension forces therein and thereby prestress the twins and a method of posttensioning panel twins by means of adjustable couplers and turn buckles.

16 Claims, 16 Drawing Figures PATENTED FEB I 1972 min-um mama res 1m $638,371

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PRECAS'I PANEL BUILDING STRUCTURE AND METHOD OF ERI'XITING THE SAME BACKGROUND OF THE INVENTION The present invention relates in general, to building structures of various kinds, and especially large, multistory buildings, such as, for example, multifamily houses, barracks, warehouses etc.

In particular, the present invention relates to a building structure and method of erecting the same which consist of a plurality of prefabricated concrete panels.

There have been known inexpensive buildings wherein the foundation, the roof, the walls, the floors and various other structural components are formed of a plurality of precast concrete modules or panels. Such modules have been disposed in edge-to-edge relationship and secured in assembled relationship by a bonding means preferably in the form of an adhesive substance which is pumped between the adjacent edge portions.

One of the disadvantages of such known structures is that long horizontal panels must be provided with permanent intermediate span support members which increase the cost and reduce the useful area of the building unless the panels are made in one piece and prestressed by a plurality of thin wires tensioned by means of expensive tensioning frames, prior to pouring of the concrete however, the transportation of oversized roof panels requires special measures and heavy-duty lifting equipment is necessary for erection.

SUMMARY OF THE INVENTION The primary object of the present invention is, therefore, to provide a secure horizontal panel structure having small weight and a large effective area without requiring inside support members, thus offering complete freedom for any layout of partitions.

Another primary object of this invention is to provide means and method for posttensioning of two and abutted generally horizontally extending panels to get a self-supporting panel twin and which can be easily erected in-between periphery wall panels.

Each of said panel twins of the present invention includes at least two horizontal panels abutting each other in intermediate span joints and provided with a pair of elongated stressed-steel bars or exposed tendons connected by means of adjustable couplers over the joints. According to one feature of the present invention these bars or tendons are connected with opposite corner portions and to another to provide a self-carrying twin without a middle-span support.

The invention resides in the combination, construction, arrangement and disposition of the various component parts and elements incorporated in improved methods of building construction and building structures constructed in accordance with the principles of this invention. The present invention will be better understood and objects and important features other than those specifically enumerated above will become apparent when consideration is given to the following details and description, which when taken in conjunction with the annexed drawing describes, discloses, illustrates and shows a preferred embodiment or modification of the present invention and what is presently considered and believed to be the best mode of practicing the principles thereof. Other embodiments or modifications may be suggested to those having the benefit of the teachings herein, and such other embodiments or modifications are intended to be reserved especially as they fall within the scope and spirit of the subjoined claims.

BRIEF DESCRIPTION OF THE DRAWINGS The manner in which the above objects of this invention are accomplished is by way of an example more fully described below with reference to the attached drawings wherein:

FIG.' la is a bottom plan view of a standard panel twin of this invention;

FIG. lb is a longitudinal vertical section of the roof panel taken on the line DD of FIG. la;

FIG. 10 is a transverse sectional view of the roof panel taken on the line A-A of FIG. la;

FIG. ld is a transverse section view of the roof panel taken on the line BB of FIG. la;

FIG. la is a transverse sectional view of the roof panel taken on the line C-C of FIG. Ia;

FIG. 2a is a detail view of a temporary seal of the joint between two roof panels of FIG. la;

FIG. 2b is a transverse sectional view of the seal of FIG. 3a taken on the line A-A of FIG. 30;

FIG. 2c is a side view of the seal of FIG. 3a on the line 8-8;

FIG. 2d is a plan view of the seal means;

FIG. 3 shows schematically the method of erecting of a roof panel twin according to this invention;

FIG. 4 is a schematical view of the arrangement of stressedsteel bars or braces, their anchors and joints on the bottom of a roof panel twin;

FIG. 5 is a section view of a tolerance adjustment coupler for stressed-steel bars;

FIG. 6 is a section view of a tightening adjustment coupler for stressed-steel bars or braces;

FIG. 7 shows schematically the jack for contraction of braces;

FIG. 8 shows a turnbuckle for fixation of the final position of stressed-steel bars or for their additional adjustment; FIG. 9 is an elevational cross section of a bolt-pipe connection according to this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings wherein corresponding parts throughout the figures are designated by equal reference numerals, there are shown in FIG. la to Is several views of a standard roof panel twin consisting of two uniform roof panels and l and l' abutting each other in middle span joint 2 and sloping in opposite directions therefrom. For the reason of simplicity, roof panel I of the twin is shown in partial view only; it will be understood, however, that the structure of panel 1 corresponds exactly with that of panel 1.

The roof panel 1 has the shape of a U-channel with sloping roof slab 3 integral with two side webs 4, three transversal ribs 5-7 tying webs 4 together and with overhanging roof part 8. The span of the roof panel twin is measured from rib 7 of panel 1 to rib 7' of panel 1', both ribs 7 and 7' being supported by the front wall structure of the building. Rib 7 is provided with anchor bolt 9 situated above the centerline of slab 3 and near to that point, a duct or hole 10 passes through the slab 3.

The duct 10 may serve to any purpose or may be covered by a concrete plug.

Rib 6, which is preferably situated in the quarter of the span, is, as seen most clearly in FIG. la, stepped inwardly to form notches 11 at a certain distance from each of lateral webs 4. The stepped portions of rib 6 are provided with correspondingly stepped slide strips 12, preferably of steel, which serve as a locking guide for stressed-steel bars or braces 13 and 14 during the first step of the tensioning process according to this invention, as it will be described hereinafter.

Rib 5 at the middle span region of the panel twin is provided with straight steel slide strip 15 for guiding the stressed-steel bars or braces 13 and 14 and has the same function as the rib 6 to give the bars 13 and 14 the desired elevation. Rib 5 is further provided with pipe 16 embedded therein above the center line of slab 3, for receiving adjustable wire rope 54 for a temporary anchorage during the tensioning process. At the top area of the middle span joint 2 there are secured two metal plates 17 in each roof panel of the twin for transferring the compression forces in the top area of roof panels during the first step of the posttensioning. Metal plates 17 can be supplemented with additional steel sheets to eliminate eventual tolerances.

The inside comers 18 of rib 7 transfer the prestressing force from plate 19" to concrete and create inside truncated cone free space for free rotation of steel anchor bolts 19 and 19'. The extended ends of these bolts 19 and 19 are threaded in opposite way and provided with couplers 20 and 21, respectively, for the connection with the longitudinal stressed-steel bars or braces 13 and 14. As it will be described in more detail below, bolts 19 and 19' are adjusted in shape to the final position of braces 13 and 14, and the anchor bolts 19 and 19 which cooperate with couplers 20 are right threaded, whereas the second one pertaining to coupler 21 is left threaded.

Rib has two connection pipes 22 embedded therein to provide, according to another feature of this invention, boltpipe connection of the twin. Similarly, longitudinal side webs 4 have a number of connection pipes 22 respectively located at vertical centerlines of the gable panels and these are employed either for connections between roof panel and gable wall panel or between roof panels and eventual transversal walls.

The outside surface of webs 4 is preferably grooved to increase adhesion of cement mortar which will be poured into the joint between adjacent webs 4 of two roof panel twins.

The function of the roof panel twins is to compensate all vertical forces by means of a posttensioned structure and to transfer horizontal forces acting perpendicularly onto the vertical walls, into circumferential shear forces.

The bolt-pipe connection as shown in FIG. 9 is created by pipe member 22 integral with an outwardly bent injection passage or tube 44. Pipe 22 with injection tube 44 are placed into the mold prior to the pouring of the concrete.

The outer surface of the pipe 22 is thus completely embedded within the body of the panel whereby the spaced apart orifices of pipe 22 and of the inlet of tube 44 remain open. The bond of the pipe 22 with the panel must be higher than the forces applied to the connection bolt 45. According to the present invention, the inside diameter of connection pipe 22 is substantially larger, almost three times, than the diameter of the connection bolt 45 passing therethrough, thus permitting a larger tolerance around the bolt and some misalignment of the pipes 22. After erection the space between the inside wall of the pipe 22 and bolt 45 is through injection tube 44 filled up with a hardening substance, such as epoxy resin or cement mortar, for example, to insure a perfectly rigid connection. After the pipe 22 has been filled, the mouth of injection pipe 44 is sealed by cork 46. The connecting force is generated by nut 43 and transferred from bolt 45 through washer 47 and pipe 22 into surrounding concrete.

The connection and tensioning of two roof panels into a single self-supporting panel twin, as well as the structure of the latter, will now be described.

Theposttensioning of two corresponding horizontal roof panels preassembled into a panel twin is based, according to the present invention, on the transversal or lateral deflection of two exposed stressed-steel bars or tendons 13 and 14 extending across the joint between the panel members I and l" and respectively anchored at opposite comers thereof. At their initial positions, bars 13 and 14 follow the path of Iongitudinal webs 4, whereas their final position is insured by transverse ribs 5 and 6.

As shown in FIG. 3, roof panels 1 and 1' may be first placed into close end-to-end position spanning the peripheral wall structures or panels, temporarily supported in the middle span area as by a foldable auxiliary support member 49. The roof panels are then fastened one to another by connections 22 and 45 in ribs 5 and 5' and to the wall panels 26 by connections 9 and 29 and temporarily held ropes 54. The resulting panel twin is provided with two galvanized stressed-steel bars or tendons 13 and 14. The bars or tendons which have right threaded ends 50 must be first inserted into freely rotatable yokes in opposite way threaded spindlers 51 and 52 for turnbuckle 53 (FIG. 8). The initial arrangement of bars or tendons l3 and 14, the direction of threaded 50 on their ends, the direction of threads of anchor bolts 19 and 19', as well as the arrangement of couplers 20 and 4, are shown in FIG. 21.

The threadings of couplers 20 and 21 are shown in more detail in cross-sectional view in FIGS. 5 and 6.

The method of posttensioning of roof panel twin l1' is as follows As mentioned above, the two panels of the twin are first aligned and placed in close position one to another on the walls 26 and 26', supported in middle span by means of temporary support member 49 and fastened to the walls. The stressed-steel bars or tendons l3 and 14 are coupled by means of couplers 20 and 21 to stressed-steel anchor bolts 19 and 19. The bars are first connected by couplers 21 whereby approximately Vz-inch spacing is left at the threaded ends thereof, then couplers 20 are turned back over the thread of anchor bolts 19. Each of the bars or tendons is aligned parallel with longitudinal webs and, in vertical projection, it is incontact with the bottom of the stiffening ribs 5 and 6. Coupler 20 is then turned on until the ends of bolt 19 and of bars or tendons are in contact. This action is followed by moderate tightening of couplers 21, thus providing a slight tension within the whole set.

Subsequently, the twins may be temporarily tied to the bottoms of the wall panels by means of wire rope 54 attached to holes 16 in ribs 5 and 5', to prevent sudden upward displacement of the roof panels in the middle span joint during the first step of tensioning process.

During the first step of the tensioning, bars or tendons l3 and 14 are first pushed transversally by means of jacks or auxiliary turnbuckles 55 (FIG. 7) into notches 11 in quarter-span ribs 6 and 6'. The horizontal compression force resulting from bias introduced in the bearing concrete section, creates a moment, due to couple of forces, which is slightly higher than that due to dead load of the twin. The close contact in compressed concrete in the joint 2 is ensured by means of two steel plates 17 (FIG. 1e) with additional steel sheets due to tolerance. Upon the completion of this first posttensioning step, the temporary support 49 in the middle span can be removed, because the joint tending to move upwards is held in position by rope 54, and joint 2 is filled up by an adhesive substance, such as epoxy resin or cement mortar, employing thereby temporary seal or mold means 60, 61 and 62 as shown in FIGS. 2a to 2d. After hardening of the epoxy resin or cement mortar, the final step of posttensioning of bars 13 and 14 is carried out in middle span between the ribs 5 and 5' by means of spindlers 51 and 52 which have been assembled into transversal turnbuckle 53 (FIG. 8). The final transversal distance of stressed-steel bars 13 and 14 is determined by computation. The second final step of posttensioning insures the coverage both of the dead load of twins and of any additional dead load including live load. After the hardening of the epoxy or cement in the center joint, each wire rope for holding is to be removed.

The above-described methods of erecting and posttensioning of building structure employs only a fraction of the force being introduced into stressed-steel bars and uses very simple jacks or turnbuckles for the transversal pushing of the bars.

The structure can be erected as a temporary one without using cement mortar and hardening adhesive substances for connections, and can be disassembled for reerection.

The building structure according to this invention enables the most economical method of erecting and employs construction elements of convenient dimensions and weights which are suitable for the transportation over long distances.

While the invention has been described, disclosed, illustrated and shown in tenns of an embodiment or modification which it has assumed in practice, the scope of the invention should not be deemed to be limited by the precise embodiment or modification herein described, disclosed, illustrated or shown, such other embodiments or modifications as may be suggested to those having the benefit of the teachings herein being intended to be reserved especially as they fall within the scope and breadth of the claims here appended.

What is claimed is:

l. A panel structure for spanning a plurality of spaced-apart supports to roof over the space therewithin comprising a pair of generally rectangular precast concrete panels disposed in end-to-end abutting relationship to define a panel twin for spanning such supports, means rigidly clamping such abutting ends together to define an intermediate span joint locked against rotation, two bodily flexible stressing tendons extending generally longitudinally over the entire span, means for anchoring the end portions of said stressing tendons at the comer positions of said panel twin opposite the abutting ends to extend across said intermediate span joint and means for moving intermediate portions of said tendons toward one another so that the intermediate portions thereof are closer together than the anchored end portions, said tendons are in tension and said concrete panels are in compression to enable the panel twin to support substantial perpendicular loading intermediate such support.

2. The panel structure according to claim 1 wherein said concrete panels each comprise a slab having peripheral frame means integral therewith and having a pair of spaced-apart end portions and two side portions, at least the adjacent ones of said end portions being provided with a number of generally aligned connection pipes embedded therein and passing therethrough in parallel with the plane of said slab of sufficient diameter to receive connection bolts therewithin with substantial clearance and being adapted for receiving a hardenable filler substance therein to surround such connection bolts and provide shear resistance at said joint even when the connection pipes are substantially misaligned.

3. The panel structure according to claim 1 wherein at least one of said concrete panels comprises an intermediate transverse rib and a middle span transverse rib; said intermediate rib having notches for locking intermediate portions of said tendons closer together than the anchored end portions and thereby in a stressed position and said middle-span transverse rib having means embedded therein for receiving said clamping means.

4. The panel structure according to claim 1 wherein said moving means comprises a turnbuckle connected with said tendons in the region of said intermediate span joint.

5. Panel structure defined in claim 1 wherein said panel members comprise mating end flange portions adjacent said abutting ends provided with connection pipes extending generally perpendicular therethrough in general axial alignment and wherein said securing means comprises a rod extending through said connection pipes having a diameter substantially smaller than the inside diameter of at least one of said pipes so that it may pass therethrough even when said pipes are substantially misaligned, means at each end of said rod engaging said flanges to clamp said flanges together and a hardened substance injected into said pipes after placement of said rod to surround said rod and fill said pipe to preclude relative lateral movement of said rod and pipe and thereby provide shear resistance between the panel members.

6. Panel structure defined in claim 5 wherein said connection pipes are of the same diameter and substantially larger than said rod so as to enable clamping even in the absence of correct alignment.

7. Panel structure defined in claim 5 wherein said rod and clamping means comprises a bolt and nut combination.

8. Panel structure defined in claim 5 wherein said hardened substance is selected from the group consisting of mortar and epoxy resin.

9. Panel structure defined in claim 5 wherein said panel members further comprise flange portions adjacent the nonabutting edges to define a peripheral reinforcing frame, said tendons being secured with said frame.

10. Panel structure defined in claim 8 wherein each of said flange portions are provided with connection pipes of substantial diameter to enable joining with other adjacent panels and supports.

11. Method of erecting a panel building structure comprising, at least the steps of, positioning a pair of generally rectangular precast concrete panel members in end-to-end abutting relationship to define a panel twin spanning a plurality of spaced-apart supports, clamping the abutting end portions of said panel members together to define an intermediate span joint locked against rotation, extending a pair of bodily flexible stressing tendons generally longitudinally in spaced-apart relationship across the intermediate span joint, anchoring the end portions of said tendons with the panel members adjacent the end portions thereof opposite the intermediate span joint and moving intermediate portions of the tendons toward each other so as to be closer together than the anchored end portions so that the stressing tendons are in tension, the concrete panels are in compression and the panel twin will be able to support substantial loading intermediate the supports.

12. Method defined in claim 11 further comprising, at least the additional step of, temporarily supporting the panel members intermediate the spaced-apart supports until tensioning of the tendons.

13. Apparatus defined in claim 11 wherein the step of moving comprises installing a pulling assembly between the tendons and activating the pulling assembly to move the tendons toward one another.

14. Method defined in claim 13 wherein the pulling assembly comprises a turnbuckle and said step of actuating comprises rotating the turnbuckle.

15. Method defined in claim 11 wherein the abutting edge 7 portions of the panel members comprise flanges having generally aligned apertures extending therethrough generally parallel the plane of the panel members and wherein the step of clamping the panel members together comprises installing bolt means through the aligned apertures and tightening a nut on the bolt to clamp the flanges together.

16. Method defined in claim 15 wherein the apertures are substantially larger than the bolts so that the bolts may pass therethrough even if the apertures are misaligned and further comprising, at least the additional step of, injecting a hardenable material into the apertures after placement of the bolts to surround the bolts and provide shear resistance thereat. 

1. A panel structure for spanning a plurality of spaced-apart supports to roof over the space therewithin comprising a pair of generally rectangular precast concrete panels disposed in end-toend abutting relationship to define a panel twin for spanning such supports, means rigidly clamping such abutting ends together to define an intermediate span joint locked against rotation, two bodily flexible stressing tendons extending generally longitudinally over the entire span, means for anchoring the end portions of said stressing tendons at the corner positions of said panel twin opposite the abutting ends to extend across said intermediate span joint and means for moving intermediate portions of said tendons toward one another so that the intermediate portions thereof are closer together than the anchored end portions, said tendons are in tension and said concrete panels are in compression to enable the panel twin to support substantial perpendicular loading intermediate such support.
 2. The panel structure according to claim 1 wherein said concrete panels each comprise a slab having peripheral frame means integral therewith and having a pair of spaced-apart end portions and two side portions, at least the adjacent ones of said end portions being provided with a number of generally aligned connection pipes embedded therein and passing therethrough in parallel with the plane of said slab of sufficient diameter to receive connection bolts therewithin with substantial clearance and being adapted for receiving a hardenable filler substance therein to surround such connection bolts and provide shear resistance at said joint even when the connection pipes are substantially misaligned.
 3. The panel structure according to claim 1 wherein at least one of said concrete panels comprises an intermediate transverse rib and a middle span transverse rib; said intermediate rib having notches for locking intermediate portions of said tendons closer together than the anchored end portions and thereby in a stressed position and said middle-span transverse rib having means embedded therein for receiving said clamping means.
 4. The panel structure according to claim 1 wherein said moving means comprises a turnbuckle connected with said tendons in the region of said intermediate span joint.
 5. Panel structure defined in claim 1 wherein said panel members comprise mating end flange portions adjacent said abutting ends provided with connection pipes extending generally perpendicular therethrough in general axial alignmEnt and wherein said securing means comprises a rod extending through said connection pipes having a diameter substantially smaller than the inside diameter of at least one of said pipes so that it may pass therethrough even when said pipes are substantially misaligned, means at each end of said rod engaging said flanges to clamp said flanges together and a hardened substance injected into said pipes after placement of said rod to surround said rod and fill said pipe to preclude relative lateral movement of said rod and pipe and thereby provide shear resistance between the panel members.
 6. Panel structure defined in claim 5 wherein said connection pipes are of the same diameter and substantially larger than said rod so as to enable clamping even in the absence of correct alignment.
 7. Panel structure defined in claim 5 wherein said rod and clamping means comprises a bolt and nut combination.
 8. Panel structure defined in claim 5 wherein said hardened substance is selected from the group consisting of mortar and epoxy resin.
 9. Panel structure defined in claim 5 wherein said panel members further comprise flange portions adjacent the nonabutting edges to define a peripheral reinforcing frame, said tendons being secured with said frame.
 10. Panel structure defined in claim 8 wherein each of said flange portions are provided with connection pipes of substantial diameter to enable joining with other adjacent panels and supports.
 11. Method of erecting a panel building structure comprising, at least the steps of, positioning a pair of generally rectangular precast concrete panel members in end-to-end abutting relationship to define a panel twin spanning a plurality of spaced-apart supports, clamping the abutting end portions of said panel members together to define an intermediate span joint locked against rotation, extending a pair of bodily flexible stressing tendons generally longitudinally in spaced-apart relationship across the intermediate span joint, anchoring the end portions of said tendons with the panel members adjacent the end portions thereof opposite the intermediate span joint and moving intermediate portions of the tendons toward each other so as to be closer together than the anchored end portions so that the stressing tendons are in tension, the concrete panels are in compression and the panel twin will be able to support substantial loading intermediate the supports.
 12. Method defined in claim 11 further comprising, at least the additional step of, temporarily supporting the panel members intermediate the spaced-apart supports until tensioning of the tendons.
 13. Apparatus defined in claim 11 wherein the step of moving comprises installing a pulling assembly between the tendons and activating the pulling assembly to move the tendons toward one another.
 14. Method defined in claim 13 wherein the pulling assembly comprises a turnbuckle and said step of actuating comprises rotating the turnbuckle.
 15. Method defined in claim 11 wherein the abutting edge portions of the panel members comprise flanges having generally aligned apertures extending therethrough generally parallel the plane of the panel members and wherein the step of clamping the panel members together comprises installing bolt means through the aligned apertures and tightening a nut on the bolt to clamp the flanges together.
 16. Method defined in claim 15 wherein the apertures are substantially larger than the bolts so that the bolts may pass therethrough even if the apertures are misaligned and further comprising, at least the additional step of, injecting a hardenable material into the apertures after placement of the bolts to surround the bolts and provide shear resistance thereat. 